48-volt electrical system

A 48-volt DC electrical system voltage is a relatively low-voltage electrical system that is increasingly used in vehicles. It began in the 2010s as a way to increase the propulsion and battery recharge during braking for fuel savings in internal combustion engine vehicles, especially mild hybrid vehicles.^[1]

Traditionally, vehicle low-voltage applications were powered by a 12-volt system. In the 1990s, an attempt by a cross-industry standards group to specify a 42-volt electrical system failed to catch on and was abandoned by 2009.^[2] During the 2010s, renewed interest arose for a 48-volt low-voltage standard for powering automotive electronics, especially in hybrid vehicles.^[3]

In 2011, German car manufacturers Audi, BMW, Daimler Benz, Porsche, and Volkswagen^[4] agreed on a 48 V system^{[clarification needed]} supplementing the legacy 12 V low-voltage automotive standard.^[5]

In model year 2017, the Renault Scenic dCi Hybrid Assist was the first 48 V mild-hybrid passenger car.^{[citation needed]}

As of 2018, a 48 V electrical subsystem operated production vehicles such as Porsche and Bentley SUVs. Audi and Mercedes-Benz used a 48 V subsystem in 2018 vehicles such as A6, A7, A8 with 3.0 TDI 48 V mild-hybrid, CLS, E-Class, S-Class with M256 3.0 Turbo Otto 48 V Mild-Hybrid.^{[6][clarification needed]}

Hyundai Tucson, Hyundai Santa Fe, Kia Ceed and Kia Sportage followed in model year 2019 with 1.6 and 2.0 turbodiesel engines supported by 48 V mild-hybrid technology.^{[citation needed]}

A European automotive trade association, CLEPA, estimated in 2018 that as many as 1 of every 10 new vehicles in 2025 would use at least one 48-volt device in the vehicle, covering 15 million vehicles per year.^[7]

In March 2023, Tesla Inc. revealed that the Tesla Cybertruck and next-generation vehicle would utilize a 48-volt mid-voltage subsystem as a replacement of 12 V system, migrating the low-voltage components with highest power demand to 48 V.^{[8][better source needed]}

In December 2023, in order to accelerate the adoption by other automakers of 48 V system voltage for automotive components, Tesla offered a "48-volt electrical system whitepaper" to all industry leaders. CEO Jim Farley confirmed that Ford had received a copy and agreed to 'help the supply base move into the 48-volt future".^[9] Tesla also adopted 48 volts for its Optimus robot.^[9]

A 48 V system can provide more power, improve energy recuperation,^[7] and allow up to an 85% decrease in cable mass.^[10]

12-volt systems can provide only 3.5 kilowatts, while a 48 V power could achieve 15 to 20 kW or even 50 kW. 48 volts is below the level that is considered safe without special protective measures.^[11]

One example of where these benefits can be used is in the Gordan Murray Automotive T.50, where it uses an integrated starter-generator to generate power for a 48 V AC compressor, without the need for a belt. This allows the engine to rev more freely and give the vehicle good AC, no matter the RPM.^[12]

Another example is with the use of electric turbochargers, active suspension, and rear-wheel steering systems that require a lot of power to run, and might be more responsive and capable with a 48 V system.^[13]

• Automotive battery
• Extra-low voltage
• Load dump
• List of electric vehicle battery manufacturers

• 48 V Vehicle Electrical System – More Than Just a Bridging Technology? Dusan Graovac, Christoph Schulz-Linkholt, Thomas Blasius, 23 April 2020, EE Times/Asia.(subscription required)
• ISO 21780:2020(en) Road vehicles — Supply voltage of 48 V — Electrical requirements and tests^{[clarification needed]}